1. Field of the Invention
The present invention relates to a speed change controlling apparatus for a motorcycle, and particularly to a speed change controlling apparatus for a motorcycle capable of executing speed change control in response to a roll angle of a vehicle body.
2. Description of Related Art
Conventionally, an automatic transmission is known which changes over meshing engagement of speed change gears by an actuator such as a motor so that the speed can be changed automatically (full-automatic) or semi-automatically (semi-automatic). Such an automatic transmission as just described automatically changes the speed based on information of an engine speed, a shift stage of the transmission, a throttle opening and so forth upon full-automatic speed change but carries out speed change operation in response to an operation of a speed changing switch mounted on a steering handle bar or the like upon semi-automatic speed change.
In Japanese Patent Laid-Open No. 2007-218269, a speed change controlling apparatus is disclosed which detects a roll angle (bank angle) of a vehicle body of a motorcycle and inhibits speed change operation of an automatic transmission if the detected roll angle is greater than a predetermined angle. With this technique, the influence of a driving force variation involved in speed change operation on the vehicle body posture or the like during cornering in which the roll angle is great can be prevented.